Treatment strategies and overall survival for incurable metastatic colorectal cancer – A EURECCA international comparison including 21,196 patients from the Netherlands and Norway

The potential benefit of surgery of the primary tumour in patients with asymptomatic metastatic colorectal cancer is debated. This EURECCA international comparison analyses treatment strategies and overall survival in the Netherlands and Norway in patients with incurable metastatic colorectal cancer. National cohorts (2007–2013) from the Netherlands and Norway including all patients with synchronous metastatic colorectal cancer were compared on treatment strategy and overall survival. Using country as an instrumental variable, we assessed the effect of different treatment strategies on mortality in the first year. Of 21,196 patients (16,144 Dutch and 5052 Norwegian), 38.6% Dutch and 51.5% (p